Electrical controlling device.



H. W. LEONARD. ELECTRICAL CONTROLLING DEVICE.

APPLICATION FILED JUNE 25 1904.

Patented May 6, 1913.'

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Patented May 0, 1913.

%&bneooeo c @vwowtoz 33n A @Hoanag H. w. LEONARD. ELECTRICAL CONTBOLLING DEVICE.

APPLICATION FILED JUNE 25, 1904.

Patented May 6,1913.

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H. W. LEONARD.

ELECTRICAL CONTROLLING DEVICE. APPLICATION FILED JUNE 25, 1904.

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w/massas INVENTOH I I I :4

Patented May 6, 1913.

v ATTORNEY tion.

I any desired value." =1:

Tozoll wlzoni,it ntagj coacernz-s-a i v Be it known that I; Leontain newand useful Improvements in Electrical Controlling. Devicesifiof whichthe following is aful l; clear, and reel: specifica:

This inventioni'elates meansfor con-i trolling the electromotive' ..forupon 'the, terminals of a translating'devicwand which is capable ofbeingembodied in many -difier-' ent arrangements of apparatus and"circuits,-i i 15 and capable of Various .apjolica'.tiolis.

'The object of my invention is to provide improved means-for.controlling-the deem: motive force applied at 'ithe ,terrhinalsxof atranslating device such as'a m f, b i' lamps, etc.- By my-ifiir'entionthe said'electromotive force may controllable-atwill and isautomatically maintainedconstant' at My invention will'be understood byreference to the following description and ace companying drawings, and"flie noveltythereof will be more particularly set forthintheclaims-Figure 1 is a an ap plication of my invention ;.for' the purpose ofmaintaining the speed ofa motor constant at any desiredvalue withvarying torque;-

Figs. 2 to 10' are diagrams illustrating various modifications andapplications of my invention. Fig. 1 discloses a inethod'and-meansrmaintaining the speed of an electric motorwhen the. torque varies: a.w'

constant when connected on =constant poten-- tial mains and subject to aiiaryin .torque. It is to be understood that the will not be absolutelyconstant-but will be constant in the same sense that-ashunt wound motoris described as a constant speed motor when operating at variabletorques a constant electromotive force circuit. It is well known .thatsucha motor,.-if-it has a considerable resistance in itsarmaturecircuiqwill Inain tain' a constant speed only when itstorque isconstant. Also in many classes :of work it isdesirable and important tooperate theimo tor at difie'rent speeds inserting resistance inthearmatureciroui6 and-to' -be abIez to maintaintconstant my; desiredsgiaed, even e-frange.

. V i i q fandin t Aim, a citizen oi the United'States, residing 1 atBronxville in the count'yojfi Westchesterand State of liew have-invented-ce'r-' 1;- amia le means 6f mye manner illustrated in 5%119 P sitiveand negative" supply maing are indicated at 1, 1" and the constant poten1 ti'alsource of electricityiis represented by Itlfef-direct currentgenerator 2 having the {field winding 3, and adjustable field re'sistais to driyendsleonnected across the mains 1 1 1m series 7 with} a":Vflliflttbli resistance 6,-

resiistance m, Yln'another circuit between the mains 1,-1'--are mcludediii-series, the arma tur'es M; G of a snia'll divided source ofelectromot'ive force oomprising'two' dynamo electrQ-armature windin of abalancer set, the armatures' being mec' anica'llyco'upled. The field 11of M has one 'terihinal-connected'to one end of the variable resistance13'and the other to the line 11'bythe connect-ion 14, and

the field 12 f'fG"l1tiS one-terminal connected tothe bpposite-endoftheresistance 18 and the: curient'passingfrom ghne l by a connection 7-toithe mastitis-rimme- The field- 9 of themotor is connotedin shuntacross the mains'and in series with a variable field the otherterminalfconnected to-line 1" as by wire 14:. The arln' 1510'::the'variable'resistance 13 is connected by-wirej16 to the'line 1.--From a point 'A in the connection between the-'armatures-M-dnd-Gwxtends a lead 17 to a point B in the coh ection between" the'i'eslstance 6 andt-hefiarmature 5 of the main- 5 1 I motor. In the lead17 isc0nnected the arnia.' 5mm 1180f a! mall-motor which drives the} arm8 by some= lnechanical connection; as

{by wt-heworm 1 9 andi t oothed extension 20' 'of arm 8. v. The field21ifor the armature 18 is connected acrossthe 1, 1 through :a fieldresistance 22'and istherefore independ ently and continually excited.{The spe the main motor'at say half speed, and for ed- "and direction ofrotation of the armature 18 .will consequently depend upon theyoltagesake of simplicity fin description the slight 3 losses in. the variousleads, armatures, etc will be considered negligible. Smce'the fieldstren h of the main motor iscon stant, half spee will be obtained bkeeping a constant electromotive' force 50 volts 0n the armatureterminals audit the potent al of line 1 is .assumed to"be"constantly' ati zero then the potential at point B. zmu'st be vmaintained at 5O.- Thepotential 'of oint B will be maintained at 50 in-the folibwi'ng manner:-The arm of the 'rheo-' stat will be placed-I a-t' th e centralposition of the resistance .13. andathe fields 11.and 12 will then beexcited equallyn-In' the opera? tion of the motor generators M, G, thearmaturesof which are similarly wound, there will then be a differenceof potential between line 1 and point A of 50 voltsan'd between oint Aand line '1': there will also be, a iiferenceof potential of 50 voltsand the potential of A -will therefore constantly remain at -50. Undernormal conditions'the potential atpointB will be, 50 and no currentwillpass through connection .17

and .the armature-18 will be at'rest.

however, the :torque of the main motor m-f creases, then, on account ofthe increased current in the armature circuit, the volts dropped on theresistance 6 become greaterthan before and the potential of point Bfalls below- 50 and the motor tends to slow .down. As soon as thepotential of B falls below 50 or that of point A, a current will flowfrom A to B through armature. 18 and the latter} will be rotated insu'ch .a direction that the arm '8 is moved so as tocut out some of theresistance 6. This will continue until the potential of -B is raised toor that of A when no current flows through armature 18 and the samecomes to rest. If the torque on the main motor decreases, then thedecreased current passing in the armature circuit will cause less dropto occur than before .on the resistance 6 and the potentialof B willthen be higher than 50 and higher: than the potential of A. This willcausea current to flow in the connection '17 from B to A through thearmature l8 which will then be rotated in a direction op osite to thatpreviously as sumed, whic -will cut more.of resistance 6 into thearmature circuit and so decrease the potential of B to-50.- The speed ofthe .mam -motor is therefore maintained conand this sirable mannergiving rapid changes of the rheostat 6 for wide variations fromnormalconditions and slow changes for slight variations from normalconditions.

By simplg movin the rheostat arm 15 the otential 0 point esired withinthejvery wide limits permitted by the voltage of the supply mains andwhenever the potential of A is adjusted to any' desired amount, thepotential of B' 'willbe regulated to the. same potential and can be.made anything the speed of the. mainmotor maintained at v acorrespondingspeed. It is evident that the controlling res1stance-18 maybe located at a distance from-the rest ofthe apparatus may be desirablein. many applications j It isl-unnecessary'to go into an extensivediscussion of how the current changes and the paths'it'follows' in theabove described apparatus, but as a specific-illustration let us sup-ose that the machine 2 generates .100 V0 ts andthat' the armature Q isabsorbing 50- ampres and operating at half speed, so that "it 'has uponits terminals 50 volts-andis absorbingtherefore 2500 Watts. Uponthermostat-6 there will be 50 volts and '50 amperes,-z'. (2. 2500.watts. The generator 2 willbeproducin 50 amperes at 100 volts, or-watts. ow let us suppose that .the torque-ofthe load changes sothatfil'iamperes'will be required to produce the.

torqueiequired. A If we assume that 61 amperes flows throu h the motorarmature due to its slowing flown under the increased torque and that Iampere in the armature 18 will produce the torque required to .drive theworm 19', then the distribution of volts, amperes and watts will be asfollows :-One ampere will be flowing from the point A to the point B,60amperes will be flowing from the line 1 through the rheostat to point Band 61 amperes will be flowing through the .motor. armature 5. It willbe noted that the rheostat 6 contained 1 ohm incircuit be fore thechange occurred since 50 amperes caused -.a drop 60 ampereszt rough theresistance of 1 ohm will cause a drop of 60 volts, consequently thepotential of the point B after the increase in load will be 40; that is,there will be a difi'erence of potentialof 10 volts tending tos'end thecurrent from A to B, and the armature of 18 will revolve at a speedcorres ndin to 10 volts to cut out resistance' om t e rheostat until thedrop on the rheostat is 50 volts with 60 amperes flow ing. The currentin M will be ampere, M

acting as a motor. G acting as a generator will produce ampere which atA will join the current of M and the joint current of 1 ampere will flowfrom A to B. The watts generated and absorbed will be as follows:

he armature 5 will be absorbing 61 amperes at 40 volts making 2440watts, the

of .50 volts. The passage of llt variation of current in 23. A

.peres at 100 volts. It will be noted that fiheGwatts absorbed by M areregenerated 'Fig. 2 illustrates a modification. of the above describedapparatus in which the controllin potential or the otential of point A,is 0 tained by means 0? a variable resistan'ce 23 connected betweenmains'l, 1', the wire 17 'being connected to the arm 24 of the rheostatwhich by its movement gives a variable potential corresponding -to thatof point A of Fig. 1. This variable resistance therefore takes the placeof the motor generator and controlling resistance 13 of Fig. 1 and thepotential of B is maintained approximately constant by the operation. ofarmature 18 in the same manner as before, the potential of B dependingupon the position ofi the rheostat arm 24, which may be changed at willto any value between the potential of the mains 1, 1 g The arrangementspecified with reference to'Fi 2 is not so desirable as that of Fig. 1in t atthe potential of A is variable with In place of the motorgenerator of F ig, 1, I may also substitute a battery, or any othersuitable source of electromotive force. Fig. 3 illustrates anarrangement in which a storage battery is used forobtaining theregulating potential; The storage batterv "25 is connected across themains 1, 1 and the arm 26 in dpassing over the various contacts connecteto the different elements of the battery will change the potential ofpoint A to whatever is desired and thus control and maintain constantthe speed of the main motor as before.

Fig. 4 illustrates my invention ap lied to the charging of storagebatteries w en the electromotive force of the line must be cut downconsiderably and when it is desirable to obtain any desired voltage andmaintain the electromotive force atthatdesired voltage. The arrangementof the regulating apparatus is the same as shown in Fig. 2'the mainmotor 5, 9 being replaced by the The arrangement shown of electricautomobiles. the voltage of which may differ widely in differentmachines.

Fig. 5 illustrates an application of my invention for the purpose ofkeeping a cur.-

.rent constant in any desired circuit, and of any desired value. Thearrangement of the regulatin apparatus is similar to that, oi F 4, t estorage battery being replaced by a certain fixed resistance 28 which isin series, with. a, variable resistance 6 and' the motor 29 or otherdevice in which it is deslred to maintain a constant current. Theregulator will keep the potential of point B constant and the currentthrough the resistance 28 will therefore be constant in amount whichwill maintain the current through thedevice 29 constant. Itis evidentthat the value of this constant current can be made any amount desiredby changmg the rheostat arm. 24. This latter arrangement may oftentimesbe of value in connection with the operation of such devices aselectrically propelled vehicles.

I Fig. 6 shows a modified form of my inventlon anda differentapplication thereof. 30 represents the armature of a generator supplyingcurrent to distributing mains 31,

31 of-a system containing translating devices 32. The field 33 of thearmature 30 is connected across the line and in series with a variableresistance 34. Connected across theline at any desired point, which maybe near the generator or at some distance therefrom as illustrated inthe present instance, is .a constant source of electromotive force suchas the battery 35 Whose electromotive force is equal to and opposes thenormal line voltage. .In series with the battery 35 is the armature 18of the small regulating motor which operates by means of the worm 19,the toothed arm 20 of the field rheostatof the main generator. The field21 of the small motor which may be excited from any source, is shownconnected across the terminals of the battery 35, and the speed anddirection of rotation of armature 18 will depend upon the electromotiveforce on its terminals. If the voltage of the line at the point'wlierethe leads 36, 36

are connected'rises above normal, then current will flow in onedirection through the armature 18 and battery 35 and the armature 18will be rotated in such a direc tion as to cut in some of the fieldresistance 34 'and so lowerthe voltage of the generator. If the voltageon the line falls below normal, then current will flow in the oppositedirection through the armature 18 and battery 35 which will cause thearmature 18 to. rotate in the opposite direction and cut out some of thefield resistance 34: and so raise the voltage of the generator. 'Aconstant electromotiveforce will therefore be automatically maintainedon the terminals of the leads 36, 36. The v electromotive forcemaintained on the mains 31, 31 may be varied if desired by including agreater or less number of cells of battery 35 in series.

Also other sources of electromotive force maiy be used in place ofbattery 35 if desired.

ig. 7 shows another modified form of my invention by which theelectromotive force of the generator may be maintained constant. Thearmature 30 of the generator Supplies current to the mains 31, 31 whichI rheostat arm 20 as before.- The fields 37 38 the line and the armatureG being connected across the line in series with the armature 18 of theregulating motor. The field 21'of the latter is connected across theline and this motor operates the worm 19- and of the armatures M, G areconnected in series across the line, the field 37 being designed toalways have a saturated field under large variations of electromotiveforce, while field 38 is under normal conditions excited much below theknee of the saturation curve. The armatures M and G are wound so that Mwill generate an electromotive force approximately equal to theelectromotive force of the line in its strong field and when conditionsare stable G will generate approximately the' same electromotive forcein its weak field and .of course in opposition to the line voltage. Whenthe electromotive force of the line rises above normal, although thespeed of M G will increase correspondingly, the electromotive forcegenerated by G will increase more rapidly than that generated by M, on aaccount of its increase in field strength due to its degree ofsaturation and a current will flow in one direction through armature 18which will move the rheostat arm of the generator so as to lower itselectroinotive force.

of the generator will therefore be maintained I constant.

Fig. 8 shows a modified form of my invention in which the torque of twosmall armatures oppose each other and which control the operation of theregulating rheostat. The parts lettered in Fig. 8 similar to those ofFig. 1 represent the same elements and are similarly connected, therebeing the constant potential generator supplying current to mains onwhich the motor 5, 9 is con nected and whose speed is to be keptconstant. On the shaft of the worm 19 are mounted two armatures 40, 41having the fields 42, 43. The armature 40 is connected across a sourceof constant electroinotive force, such as the battery 44, through avariable resistance 45. The armature 41 is connected across theterminals of armature 5 in series with the adjustable resistance 46. Thefields 42, 43 are shown connected across the When the line voltage fallsbelow normal, the electromotive force generated terminals of the battery44 and so have a constant strength. The connections are such that thetorque of armature 4O opposes that of 41 and under normal conditionsthese armatures are at rest. If the ele'ctromotive force applied to thearmature 5 rises above normal, the electromotive force applieditoarmature 41 will increase correspondingly" which will increase thetorque of armature 41. The greater torque of armature 41 will thenoverbalance that of 40 and the rheost-at' arm 8 will be moved in such adirection as: to insertmore of resistance 6 and lower the.

electromotive force-of the armature 5. If the latter elect-romotiveforce falls below normal, then the constant torque of 40 willoverbalance that" of 41 and "arm 8 w'illbe moved in the oppositedirection so as to in-.

crease the electromotive force at armature 5. This electromotive forceand consequently the speed of armature 5 will therefore be automaticallykept constant whatever the load on. the motor may be. The

Where great sensitiveness is desired and the regulation is to be keptwithin very close limits, I may introduce a polarized relay to controlthe operation of the variable adjusting means. I will describe such arelay control as applied in connection with the apparatus of Figs. 1 and7, but it will beunderstood that the same may be applied as well toother instances. I

Referring to Fig. 9, the parts similarly indicated represent the sameelements as in Fig. 1. In place of armature 18- b eing in serted in theconnection 17 however, 47 is connected therein. This coil is providedwith a core 48 and has a pivoted armature 49. The latter has a constantpolarity, in this instance being excited by a coil 50 connected acrossthe line through'suitable resistance. A connection 51 extends from thearmature 49 to the main 1. A reversible motor is used to drive the worm19 and is indicated by an armature 52 connected across the line and inseries with a the coil ance 6 so as to raise the potential ofointcontact 58. Current will then' flow fromdriven inopposite direction andthe resist-.

rmature 49 to be attracted or repelled;

- larly indicated represent the same elements Fig. 9, with a core 48,the polarity of which $0 or 55 of the reversible motor to the othersistance 34 to be'adjusted accordingly. Thecoil 47. Suppose'the'j'pOtentiaIofB falls 'below thet of A. The polarity of 48 will thenbe such, let us say, as to attractiarmature 49 and cause itsengagementwith con-- 5- tact 57. Current will then flow from main 1 throughfield'54 tocontact-57 and then to. armature 49 and by; lead 51 "to main1'. This will cause the armature 52 to'revolve.

in such a direction as to change the B. If the potential of B becomeshigher than that of A, then-current will flow in the .opposite'direction through coil-47 and ar-, mature 49 will be repelled so as toengage:

main 1 through field "winding 55 to contact' '58, armature 49, lead 51to main, 1 Since field '55 is wound reversely with reference} to field54, the armature 52 will then be ance 6 will be changed so as tolower-jthe potential of B. This arrangement may be: made very sensitive,as only a slight current through coil 47 will be suflicient to cause ar--An application of the polarized relay to "the construction indicated inFig. 7 in order ,to secure additional sensitiveness of-op'eration, isshown in Fig. 10.-"-The parts -si1ni-- as in Fig. 7. Instead ofconnecting the ar- -mature18 in series with the armaturegG across the"line, the coil 47 isconnected therewith. The coil 47 is provided,- as independs upon the direction of current through 'coil 47. 'co6perati0nwith the core 48 is thepivoted armature 49'having a constant polarity,beingexcited by a 'coil' 50 connected across thev line. The connection51 is shown extending from the armatnre49 to one side of the line. Themotor for driv-. ing the variable resistance device to controlresistance 34 is reversible and is controlled by the actionof thepolarized relay as in Fig. 9. The parts in Fig. 10 correspondin to thoseof Fig. 9 are similarly designs, and operate as explained with referenceto Fig. 9. In the modification shown'in Fig. 10, the rise or fall of theelectromotiveforce of the line will cause a current to flowfin onedirection or the other through the ing 47 as'explained with reference toFig. 7- and the armature 18. The armature 49 55 will consequently: moveto one sideorthe other making connection either with contact 57 or 58.Current will then passsfrom one side of the line through connection 51and armature 49, and through field winding 54 side of-the line- -Thearmature 52 of the reversible motor will therefore rotate in a'netically induced electromotive force, a dedi'rection corresponding tothe direction of current through coil 47 and cause therelimited themodifications;shown and de- ,ofiieration is therefore entirely similarto t at described with referencev to Fig. 7, ex-

cept that greater sensitiveness is secured by interp the-rela fdescribed specifically the use 'of 'a' continuous current, it will beevident .thatmy'inveiitioh may 'be applied to any current whichispractically unidirec- 'tional in its niagnetic efiects. Y

--While in '-most%" fformsf shown the'two sources of F. arfeelectrically connectedit will be evident that my-inventicn is applicableto many instances'inwhichthe two sources of electromotive force" are notelectrically' connected and 'it 'is evident that my invention iscapable" or being carried into.

practice in many difl'erent-ways'and capable of various applications,and that I- am not scribed.

'HavingthusPdescribed' my invention, I

declare that what--I'-claiin as new. and desire to secure by-LettersPatent, 'is,

1. The combination" jot al'sour'ce' of magnetically-inducedelectromotive force, a device having -an opposing'j-magnetically'induced electromotive' forceifmeans for controllably-var'yin'gthe'electronibtive force of .said device,"" said;; opposing'electromotive force under, normal conditions having a 5 value fixed.relative to'" that' of the first =named electroniotive force,ja' "deviceresponsive to any change in 'the' relative valuesof said electro'motivef forces; 'and means 'controlled by said"sec'ond device for restoring 00the 'desired relationbetween the two 'electromotive forces. 4

'2. The combination with a source of magnetically induced electrornotiveforce, of a device having an electromotive force opposmg theelectromotive force of said source, a common source of electric enerupon which bot-hiof said electromotive orces are continually dependent,a device responsive to the difi'erence between said 'electromotive 1forces, and means controlled bysaid second device'for changing one ofthe electro'motive' forces to preserve adesired relation between 3 Thecombination'with a source cf-mag- 1' netically induced electromotive-forc e,-'iofa device having an opposing -electromotive force, a commonsource of energy upon which bothof said electromot'iveforces arecontinuall dependent, a device responsive to the di erence'between theelectromotive forces and connected ,in circuit with said first 'namedsource and first named. device, and means controlled by-said seconddevice 'for changing one of the electromotive forces to'preserve adesired relation between them.

4. The combination of a source of magvlce having an" opposingmagnetically induced electromoti've iorce, said device hav- -1'30trollably varying said opposing electromo- .tive force, a deviceresponsive to the difference between the electromotive forces, one

electrcmotive force tending to move said de-' vice in one direction, andthe other electre motive force tending to move the same in the oppositedirection, and means controlled by said second device for changing oneof the electromotive forces to preserve av desired relation between itand the otherrelec'- tromotive force. a

5. The combination with a source of electromotive force, a translatindevice, an adjustable rheostat for controlfing the elect-romotive forceapplied-to said device,'a second source of electromotive force whoseelectromotive force may be madethat desired on said device, electrical.connections between said second source and said device, an -elec-'troresponsive devicein circuit with vsaid connections, and meansconnected with said electroresponsive device for varying said rheostat.

6. The combination with vasource of constant e'lectromotive force andsupply mains,

of a translating device and a variable resistance connected in seriestherewith and between said supply mains, a second source of--electromotive= force "opposmg'athe electromotive force applied tosaiddevice, an elec-. troresponsive device in series with said translatingdevice and said second source of electronictlve force and controlled bythe difference between the electromotive force applied to said deviceand that of said second source, and means operated by saidelectroresponsive device 'for varying said resistance; p

7-. .The combination with the supply mains, of a translatin device, arheostat in series with said trans ating-device, and means comprising awinding connected in a' permit-- nently closed circuit and subjected tocurrents in opposite directions and controlled by variation in theelectromotive force at the terminals of said translating device for.automatically controlling said rheostat so as to maintain adesiredconstant electromotive force on said translating device;

8. The combination with mains, of constant electromotive force, of .amotor whose speed is to be kept constant, said motor having a. constantfield strength, an adjustable resistance in series with the armaturecircuit of said motor across said mains, aregulating source ofelect-romotive force, an electroresponsive device in circuit with said'7 regulating source and motor armature, and means controlled by saiddevice for. varying said adjustable resistance.

9. The combination with a source of practically constant electromotiveforce, a translat-mg device connected across the circuit lating device,a divided source otehcfiro;

motive force also connected across saidlcir v cuit, a lead connectingthe point of division of said divided source of 'electromotiveforce andpoint; intermediate. said]rheostat and said translating device, and anauxiliary motor for operating said rheostat, said auxiliary motor haviin circuit with'sai lead.

' 10. The combination of a source of 'electromotive force'and a supplycircuit, ,a'.".transits armature -connected ia-ting device connected tosaid circuit, and

means for automatically maintaining constaiit the potential at oneterminal .of said translating device comprising an electroresponsivedevlce electricallyconnected to said terminal and-responsive to currenttherethrough'in opposite directions which acts toeorrect change from thedesired combination of a source of electremotive force and asupply-circuit, a translating device connected to said circuit, and

- means 'fora-utomatically maintaining the potential at one terminal of.said' translating' device constant comprising an adjustable element, anelect-norespon'sive controlling winding connected "in apermanentlyclosed circuit and subjected to currents in opposite directions, andelectricaliconneetions causing said'element to move in one directionwhen the potential rises'above the desired potentzial and to move-in theop osite direction when the potential falls be ow the desired changesfrom the desired potential. a

12. The combination ofa source of electromotive force and supply mains,a.trans- 'lati device connected therewith, a ,movable evice forcontrolling the .electromotive force a plied to said translating device,means or obtaining any desired constant .electromotive force, and anel'ectroresponsive device connected with said means and with saidtranslating device for controlling the movement of said movable deviceto maintain desired constant conditions 13. The combination of a sourceof electromotive force and supply mains, a transpotential and therebycompensate for lating device connected therewith, a movable saidtranslating device and to the circuitupon which the constantelectromotive force is impressed for automatically controlling themovement of said movable device to maintain practically the sameelectromotive 'force at the terminals of said translating device.

16. The combination of a source of electromotive force and supply mains,a motor, a movable device for varying the electromotive force suppliedto" the armature terminals of said motor, adjustable means for obtainingany desired constant electromotive force, and an electroresponsivedevice electrically connected to said armature and to the circuitcontaining the desired constant electromotive force for automaticallycontrolling the movement of said movable de-' vice to maintain acorresponding constant electromotive force at the terminals of saidmotor armature. 7

17.- The comblnation of a source of electromotive force and supplymalns, a motor,-

an adjustable resistance in series with the motor armature across saidsupply mains, means for obtaining a desired constant electromotiveforce, and an electroresponsive device electrically connected to saidarmature and to a circuit having the said con. stant electromotive forceimpressed thereon for automatically controlling the amount of saidresistance in series with the motor armature to maintain thecorresponding constant electromotiveforce at the terminals of said motorarmature.

18. The combination of asource of electromotive force and supply mains,a translating device and a variable resistance connected in seriesacross said supply mains, means for obtaining a desired constantelectromotive force, and an electroresponsive device electricallyconnected with said translating device and to a circuit having the saidconstant electromotive force impressed there on for automaticallycontrolling the amount of'said resistance in series with saidtranslating device.

19. The combination of a source of electromotive force, a translatingdevice, means for obtaining a desired constant electromotive force, amovable device for varying the electromotive force a plied to saidtranslating device, and an e ect-roresponsive device which is subjectedto the diflerence between said constant electromotive force and thatapplied to said translating device for automatically controlling themovement of said movable device.

20. The combination of an electric circuit,

means for impressing an electromotive force thereon in one direction, atranslating device in said circuit, means for applying. an electromotiveforce to said translating device which opposes the saidimpressedelectromotive force in said circuit,- an adjust able device forvaryingthe electromotive force applied to said translating device, andelectroresponsive means responsive r to the difi'erencebetween saidimpressed electromotive force and the electromotive force applied tosaid translatingdevice for automatically controlling said adjustabledevice to causethe electromotive force applied to said translatingdevice to equal said impressed electromotive force.

-21. The combination of an electric circuit, means for impressing anelectromotive force thereon in one direction, a translating device insaid circuit, means forapplying'an electromotive force to the saidtranslating device which opposes the said impressed electromotive forcein said circuit,-an' ad-.

justable device for varying the electromotive force applied to the saidtranslating device,

a relay device controlled by current in said circuit, and an electricmotor controlled by said relay for varying one of said electro motiveforces with reference to the other for maintaining the desired relationbetween them. f

22. The combination of an electric circuit, means for impressing anelectromotive force thereon in one direction, a translating deviceinvsaid circuit, means for applying an electromotive force to saidtranslating device which opposes said impressed electromotive force inthe said circuit/an adjustable device for varying the electromotiveforce applied to the said translating device, a relay device responsiveto the difference between said impressed electromotive force and theelectromotive force applied to said translating device, and meanscomprising an elec tric motor controlled by said relay device foraffecting said translating device for causing one of said electromotiveforces to balance the other.

23. The combination of a source of electromotive force and supply mains,a translating device connected therewith, a movable device forregulating the electromotive force applied to said translating device,means for obtaining a desired constant electromotive force, a relaydevice responsive to the difi'erence in electromotive force between thatapplied to said translating device and said constant electromotiveforce,

' said constant electromotive force and to that.

appli d to said translating device,.a relay device in said circuit andresponsive to the difference between electromotive torces ap pliedthereto, and an electric motive device whose direction of movement iscontrolled by, said relay for balancingthe electrcmotiveforces tomaintain the said desired relation.

forces in said circuit. a

'25. The combination of a source of ele c-' tromotive force and Supplymains, a motor,

a movable device for varying the electro-. motive force applied to thearmature ter-' minals of said motor, means for obtaining a desiredconstant electromotive force, a circuit subjected to said constantelectromotive force and to that applied to the said motor armature, arelaydevice in said circuit and responsive to the difierence be-; tweenthe electromotive forces applied thereto, and an electric motive devicewhose direction of movement is controlled by said relay for controllingsaid movable device.

- 26. The combination of a source of electromotive force and supplymains, a translating device and a variable resistance con nected inseries across said supply mains,

means for obtaining a desired constant elec--, tromotive force, acircuit subjected to said constant electromotive force and to that:-applied to said translating device, a relay device in said circuit andresponsive to. the dl-fi'erence between the electromotive forces appliedthereto, and an electric motive -de-; vice whose dlrcction of movement1s controlled by said relay for controlling said value, andelectroresponsive means responvariable resistance.

27. The combination w1th a source of constant electromotive force andsupply mains, of a translatingdevlce and a device having means forvarying the electromotivc force at its terminals connected In series andelectroinotive force opposing second source of electromotive force, and

means operated by said electroresponsive detive force in said circuit,an adjustable device for controlling said second device.

28. The combination of a source of elec-v tromotlve force, a translatingdevice, means 1 lnoenitu plied -to said translating device forautomatically controlling said device.

Q9. The combination of an electric circuit, means for impressing anelectromotive force thereon in one direction, a translating device insaid'circuit, means for applying an electromotive force to saidtranslating device which has a desired relation to and which opposessaid impressed electromotive force in said circuit, an adjustable devicefor varying one-0f said electromotive forces, a relay device controlledby current in said circuit,

and means. control d by said relay device for affecting said adjust-abledevice and thereby varying one of said electromotive 30. The combinationwith an electric motor and a source of supply therefor, of automaticspeed regulating means, comprising a device for obtaining anelectromotive force, and an electrorcsponsive means responsive to theo1nt eifect of the motor electromotive orce and the electromotive forceof said device for controlling the speed of the motor.

31. The combination with a source of supply and a translating device onthe tar minals of which it is desired to control the electromotiveforce, of means for producing an electromotiveforce, andelectroresponsivc means responsive to thejoint efiect of the'electromotive force produced by said means and the electromotive forceon the translating device for automatically controlling theelectromotivc force on the translating de- V108.

32. The combination of a constant electromotive force supply circuit, atranslating device supplied therefrom and upon whose terminals it isdesired to. maintain .a constant electromotive force different from thatof the supply circuit, means for obtaining a controllable electromotiveforce of a desired vice for varying one of said electromotive forces, aresponsive electromagnetic winding connected in said circuit, and meanscontrolled by said responsive winding for automatically controlling saidadjustable device.

34. The combination of a circuit upon which it is desired to maintain adefinite condition, two electromagnetic devices each havingelectromotive force, the said devices being connected in circuit was tohave their electroniotive forces oppose each other, and a deviceresponsive to the joint effect of said electromotive forces forautomatically maintaining the desired condition on said first namedcircuit.

35. The combination of a circuit connection upon which it is desired tomaintain a substantially constant electrical condition, a circuitconnection containing an electroresponsive winding in which the currentis normally zero, two opposing dynamo electromotive force producingdevices in series with each other and with said winding and acting tocause a current to automatically flow in one direction through saidwinding when said electrical condition varies in one sense and to causea current to automatically flow in the other direction through saidwinding when said electrical condition varies in the other sense, andmeans affected thereby for automatically restoring the desiredelectrical condition.

36. The combination of a constant electromotive force supply circuit, anelectric moan electromagnetic winding and an electromotive forceproducing device connected in a circuit extending from a point betweenthe connection of said armature and said rheostat to one of the mains ofsaid supply circuit, and means controlled by said winding forautomatically increasing and decreasing the resistance of said rheostatfor automat1- cally controlling the speed of the motor.

' 37. The combination of a constant electromotive force supply circuit,an electric motor, an adjustable rheostat connected in series with thearmature of said motor across said circuit, an auxiliary electromotiveforce producing device, and automatic means functionally related theretofor automatically controlling the amount of resistance of said rheostatin series with said armature whereby a constant speed of the motor isautomatically maintained.

38. The combination of a source of electroniotive force, an electricmotor, a rheostat in series with the armature of said motor, automaticelectroresponsive means for varying the resistance ofsaid rheostat forautomatically maintaining upon the motor armature a substantiallyconstant electromotive force said means comprising a controlling windingresponsive to a reversal of current, and adjustable means for causingsaid automatic means to maintain anydesired constant electromotive forceupon said motor armature.

39. The combination of a source of supply, an electric motor, a speedregulating rheostat connected .in series with the armature thereof, andautomatic means responsive to a change in the potential of the pointbetween the rheostat and said motor armature for automatically varyingthe resistance of 1 said rheostat and thereby automatically controllingthe speed of the motor, said automatic meanscomprising a controllingwinding and also comprising means for reversing the current in saidWinding to automatically vary the resistance and thereby control thespeed of the motor. i

40. The combination of a constant electromotive force supply circuit, anelectric motor, a speed controlling rheostat therefor connected inseries with the armature of said motor across said circuit, a secondcircuit connected across said supply circuit and containing means forproducing a potential intermediate that of the supply conductors, aconductor from a point of intermediate potential in said second circuitto a point between the motor armature and said rheostat, and meanscomprising an electroresponsive device in said conductor forautomatically controlling said rheostat.

41. The combination of constant electromotive force supply mains, anelectric motor, a rheostat connected in series with the armature 'ofsaid motor across said mains, means comprising a conductor for obtainingupon said conductor a substantially fixed potential between thepotentials of said mains, an electroresponsive device connected incircuit between said conductor of fixed potential and the portion of thecircuit between .said motor armature and said rheostat, and meansresponsive to current in said device for automatically varying theresistance of said rheostat.

42. An electric motor the torque of which is variable under conditionsof practice a source of supply therefor and means for automaticallymaintaining the speed of the motor at any desired speed, said meanscomprising a controlling magnetic winding subjected to a currenttherethrough in one di- 110 rection when the motor speed goes beyond alimit in one sense and subjected to a current therethrough in thereverse direction when the motor speed goes beyond a limit in the othersense.

43. An electric motor, a source of supply therefor, a winding connectedtherewith, means for causing a current to flow in one direction throughsaidv winding when the motor speed exceeds a certain limit and forcausing a current to flow through said winding in the reverse directionwhen the motor speed falls below a certain limit, and means controlledby said winding for automatically holding the speed of the motor betweensaid limits.

44;. The combination of a source of electric energy, a device having anelectromotive force developed in it by magnetic induction, theelectromotive force of which and the current therethrough varies inresponse to uncontrollable changes in conditions of practice, a devicefor varying the individual electromotive force applied thereto and formaintaining thereon a desired electromotive force less than that of saidsource, and automatic means for controlling said varying deviceresponsive to change from said (Lesired electromotive force, said meanscomprising a In testimony whereof I afiix my signature,

in presence of two Witnesses.

H. WARD LEONARD.

Witnesses:

CAROLYN G. LEONARD, L. K. Sacra,

device having an electromotive' l0 force developed 1n 1t by magnet cinduction connected across said source.

